Aussie scientists could make building offshore windfarms more affordable, thanks to their adaptation of a popular fishing tool.
Research engineers from RMIT University’s Heavy Structure Laboratory unveiled a new ocean soil testing device, which they hope will lead to positive construction cost changes within the renewable energy sector.
Based on a modified speargun, the technology offers offshore wind construction teams a cheaper and more efficient way to test seabed soil suitability during the design and planning phase.
The gun fires a probe into the seabed, which collects and transmits vital data to construction teams, helping them make decisions on site eligibility and possible construction methods.
University scientists tested the new launching device on various surface types within a water tank, using sensors and high-speed cameras to capture results.
They found their speargun device to be twice as effective in penetrating seafloor compared to traditionally used methods.
Speargun ‘impales’ in comparison to past tech
Currently, offshore wind farm engineers test sites by winching or dropping probes, known as penetrometers, from the deck or a support vessel.
These devices are notoriously ineffective at penetrating seafloors within shallow waters, while heavy-duty probes that do work in those environments add an extra $200,000 per day to construction costs.
Lead study author and PhD candidate Junlin Rong says the results, now published in the Canadian Geotechnical Journal, show the new device’s potential to revolutionise the offshore wind farm construction process.
“In laboratory environments, the device showed considerably greater penetration potential compared to free-falling probes on soil,” Rong says.
“Notably, in high-density sandy material, the penetration depth was twice that of previously reported values achieved by freely falling probes.”
“This breakthrough technique has the potential to revolutionise site investigations for wind farm projects, offering significant time and cost savings while outperforming the embedment achieved by other dynamic penetrometers.”
Meanwhile, by simultaneously reducing the number of expensive tests needed, construction firms could land substantial construction cost savings.
Device spearheads more sustainable build
While the device isn’t expected to replace more heavy-duty testing methods anytime soon, its retrievable launching system and cost-effective deployment mean it could boost the sustainability of the construction process.
Probes can be retrieved and reused after data collection, allowing ‘probe and go’ testing that minimises disturbance to the seabed. The technology can also be adapted to existing probes, allowing engineers to retrofit their current devices with minimal investment or material waste.
RMIT Professor of Geotechnical Engineering Majid Nazem says the next step was to deploy for real-world field trials.
“Our experiments have demonstrated the device’s ability to achieve considerable embedment depth in dense sand,” he says.
“We are keen to conduct field trials and collaborate with our potential industrial partners to further test its performance for offshore geotechnical engineering applications.”
